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The ages of A and B are presently in the ratio of 5 : 6 respectively. Six years hence, this ratio became 6 : 7 respectively. What was B's age 5 years ago ?

125 years
230 years
331 years
436 years

Answer:- 1

Explanation:-

Solution:

Let A's age be 5x years.
Then, B's age = 6 years

\begin{aligned} ∴ \frac{5 x + 6}{6 x + 6} \\ \Rightarrow 7 (5 x + 6) = 6 (6 x + 6) \\ \Rightarrow 35 x + 42 = 36 x + 36 \\ \Rightarrow x = 6 \end{aligned}

$\eqalign{ & \therefore \frac{{5x + 6}}{{6x + 6}} \cr & \Rightarrow 7\left( {5x + 6} \right) = 6\left( {6x + 6} \right) \cr & \Rightarrow 35x + 42 = 36x + 36 \cr & \Rightarrow x = 6 \cr}$
B's age 5 years ago = (6x - 5) years
= (6 × 6 - 5) years
= 31 years

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B's age 5 years ago = (6x - 5) years
= (6 × 6 - 5) years
= 31 years ", "dateCreated": "7/24/2019 10:09:12 AM", "author": { "@type": "Person", "name": "Nitin Sir" } }, "suggestedAnswer": { "@type": "Answer", "text": "

Solution:

Let A's age be 5x years.
Then, B's age = 6 years

\begin{aligned} ∴ \frac{5 x + 6}{6 x + 6} \\ \Rightarrow 7 (5 x + 6) = 6 (6 x + 6) \\ \Rightarrow 35 x + 42 = 36 x + 36 \\ \Rightarrow x = 6 \end{aligned}

$\eqalign{ & \therefore \frac{{5x + 6}}{{6x + 6}} \cr & \Rightarrow 7\left( {5x + 6} \right) = 6\left( {6x + 6} \right) \cr & \Rightarrow 35x + 42 = 36x + 36 \cr & \Rightarrow x = 6 \cr}$
B's age 5 years ago = (6x - 5) years
= (6 × 6 - 5) years
= 31 years ", "dateCreated": "7/24/2019 10:09:12 AM" } }

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